Derivation and reliability of kinematic measures of sperm motion

1995 ◽  
Vol 7 (4) ◽  
pp. 857 ◽  
Author(s):  
RO Davis ◽  
RJ Siemers
Keyword(s):  
Equations Of Motion ◽  
Biological Mechanisms ◽  
Kinematic Data ◽  
Head Kinematics ◽  
Accuracy And Precision ◽  
Engineering Measures ◽  
Kinematic Measures ◽  
Sperm Motion ◽  
Standard Techniques ◽  
Sperm Movement

Studies of sperm movement are relevant in the diagnosis of sperm function and in investigations of cellular biology. Such studies have been traditionally performed by analysing the kinematics of the flagellum or the head. Analysis of the flagellum can provide insights into the cell biological mechanisms responsible for the control of movement. However, the mathematical correspondence between head kinematics and flagellum kinematics is not unique. Therefore, it is not possible to use head kinematics to obtain detailed insights into cell mechanisms or physiology. The accuracy and precision of kinematic measurements are limited by a number of technical and biological factors. Therefore, the interpretation of kinematic data is dependent on a thorough understanding of the assumptions and conditions underlying the analysis. Evaluation of the reliability of kinematic measurements has suffered because no absolute standard for measurement has existed. The development and application of a new standard based on images which were simulated using the equations of motion is described. Because the kinematics of these images are known prior to empirical measurement, the performance of different methods can be determined absolutely. Some kinematic measures are unreliable because they are inappropriate analogues for engineering concepts. The development and use of appropriate engineering measures for the frequency and amplitude of sperm motion is also described. Some types of sperm motion cannot be analysed using kinematic measures (e.g. hyperactivated movement). The concept of the fractal dimension as a more accurate measurement for such motions is introduced. It is concluded that kinematic measurements of sperm motion can provide valuable information about cell biological mechanisms (in the case of the flagellum) and about general membrane and axoneme function (in the case of the head) when the measurements are made under the appropriate conditions, when standard techniques are followed, and when the assumptions underlying the analysis are well understood.

scholarly journals Scaling of Dynamics in the Earliest Stages of Walking

2007 ◽  
Vol 87 (11) ◽  
pp. 1458-1467 ◽  
Author(s):  
Kenneth G Holt ◽  
Elliot Saltzman ◽  
Chia-Ling Ho ◽  
Beverly D Ulrich
Keyword(s):  
Developmental Delays ◽  
Physical Therapist ◽  
Equations Of Motion ◽  
Fine Tuning ◽  
Spring Stiffness ◽  
Kinematic Data ◽  
Ground Testing ◽  
Stage Process ◽  
Study Participants ◽  
Isometric Muscle

Background and Purpose Although the description of mature walking is fairly well established, less is known about what is being learned in the process. Such knowledge is critical to the physical therapist who wants to teach children with developmental delays. The purpose of this experiment was to test the notion that learning to walk efficiently involves fine-tuning the body’s controllable stiffness (by co-contraction and isometric muscle contractions against gravity) to match (at a 1:1 scaling) the gravitational (pendular) stiffness of the swing leg. Subjects The study participants were 7 children with typical development and the newly emerged ability to walk 6 steps without falling (ages 11 months to 1 year 5 months at the onset of walking). Methods Pendular stiffness and spring stiffness were estimated from the equations of motion for a hybrid model with kinematic data as children walked over ground. Testing occurred once per month for the first 7 months of walking. Results After the first month of walking, children walked with greater spring stiffness than would be predicted by the model. The ratio began to approach the predicted value (1:1) as the months progressed. Discussion and Conclusion The results of this and a previous study of the pendular dynamics of gait suggest that learning to walk is a 2-stage process. The first stage involves the child’s discovery of how to conserve energy by inputting a particular muscular force at the correct moment in the cycle. The second stage involves the fine-tuning of the soft-tissue stiffness that takes advantage of the resonance characteristics of tissues. In order to address developmental delays, investigators must discover the dynamic resources used for the activity and attempt to foster their development. A number of interventions that probe this approach are discussed.

scholarly journals Development of the Home based Virtual Rehabilitation System (HoVRS) to remotely deliver an intense and customized upper extremity training

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Qinyin Qiu ◽  
Amanda Cronce ◽  
Jigna Patel ◽  
Gerard G. Fluet ◽  
Ashley J. Mont ◽  
...  
Keyword(s):  
Upper Extremity ◽  
Chronic Stroke ◽  
Hand Rehabilitation ◽  
Kinematic Data ◽  
Virtual Rehabilitation ◽  
Home Based ◽  
Rehabilitation System ◽  
Kinematic Measures ◽  
And Training ◽  
Training Protocol

Abstract Background After stroke, sustained hand rehabilitation training is required for continuous improvement and maintenance of distal function. Methods In this paper, we present a system designed and implemented in our lab: the Home based Virtual Rehabilitation System (HoVRS). Fifteen subjects with chronic stroke were recruited to test the feasibility of the system as well as to refine the design and training protocol to prepare for a future efficacy study. HoVRS was placed in subjects’ homes, and subjects were asked to use the system at least 15 min every weekday for 3 months (12 weeks) with limited technical support and remote clinical monitoring. Results All subjects completed the study without any adverse events. Subjects on average spent 13.5 h using the system. Clinical and kinematic data were collected pre and post study in the subject’s home. Subjects demonstrated a mean increase of 5.2 (SEM = 0.69) on the Upper Extremity Fugl-Meyer Assessment (UEFMA). They also demonstrated improvements in six measurements of hand kinematics. In addition, a combination of these kinematic measures was able to predict a substantial portion of the variability in the subjects’ UEFMA score. Conclusion Persons with chronic stroke were able to use the system safely and productively with minimal supervision resulting in measurable improvements in upper extremity function.

scholarly journals Cancer survivors post-chemotherapy exhibit unique proprioceptive deficits in proximal limbs

2021 ◽  
Author(s):  
Allison B. Wang ◽  
Stephen N. Housley ◽  
Ann Marie Flores ◽  
Timothy C. Cope ◽  
Eric J. Perreault
Keyword(s):  
Cancer Survivors ◽  
Sensory Neuropathy ◽  
Motor Dysfunction ◽  
Control Group ◽  
Alternative Mechanism ◽  
Proprioceptive Information ◽  
Kinematic Data ◽  
Force Matching ◽  
Accuracy And Precision

Abstract Background: Oxaliplatin (OX) chemotherapy for colorectal cancer is associated with adverse neurotoxic effects that can contribute to long-term sensorimotor impairments in cancer survivors. It is often thought that the sensorimotor impairments are dominated by OX-induced sensory neuropathy that primarily affects the distal regions of the limb. Recent preclinical studies have identified encoding dysfunction of muscle proprioceptors as an alternative mechanism. Unlike the sensory neuropathy affecting distal limbs, dysfunction of muscle proprioceptors could have more widespread effects. Most investigations of chemotherapy-induced sensorimotor impairments have considered only the effects of distal changes in sensory processing; none have evaluated proximal changes or their influence on function. Our study fills this gap by evaluating the functional use of proprioception in the shoulder and elbow joints of cancer survivors post OX chemotherapy. Methods: We implemented three multidirectional sensorimotor tasks: force matching, target reaching, and postural stability tasks to evaluate various aspects of proprioception and their use. Force and kinematic data of the sensorimotor tasks were collected in 13 cancer survivors treated with OX and 13 age-matched healthy controls. Results: Cancer survivors exhibited less accuracy and precision than an age-matched control group when they had to rely only on proprioceptive information to match force, even for forces that required only torques about the shoulder. There were also small differences in the ability to maintain arm posture but no significant differences in reaching. The force deficits in cancer survivors were significantly correlated with self-reported motor dysfunction. Conclusions: These results suggest that cancer survivors post OX chemotherapy exhibit proximal proprioceptive deficits, and that the deficits in producing accurate and precise forces are larger than those for producing unloaded movements. Current clinical assessments of chemotherapy-related sensorimotor dysfunction are largely limited to distal symptoms. Our study suggests that we also need to consider changes in proximal function. Force matching tasks similar to those used here could provide a clinically meaningful approach to quantifying OX-related movement dysfunction during and after chemotherapy.

scholarly journals Development of the Home based Virtual Rehabilitation System (HoVRS) to Remotely Deliver an Intense and Customized Upper Extremity Training

2020 ◽  
Author(s):  
Qinyin Qiu ◽  
Amanda Cronce ◽  
Jigna Patel ◽  
Gerard G Fluet ◽  
Ashley Mont ◽  
...  
Keyword(s):  
Hand Function ◽  
Chronic Stroke ◽  
Hand Rehabilitation ◽  
Kinematic Data ◽  
Virtual Rehabilitation ◽  
Home Based ◽  
Rehabilitation System ◽  
Kinematic Measures ◽  
And Training ◽  
Training Protocol

Abstract Background: After stroke, sustained hand rehabilitation training is required for continuous improvement and maintenance of distal function. Methods: In this paper, we present a system designed and implemented in our lab: the Home based Virtual Rehabilitation System (HoVRS). Fifteen subjects with chronic stroke were recruited to test the feasibility of the system as well as to refine the design and training protocol to prepare for a future efficacy study. HoVRS was placed in subjects’ homes, and subjects were asked to use the system at least 15 minutes every weekday for 3 months (12 weeks) with limited technical support and remote clinical monitoring. Results: All patients completed the study without any adverse events. Subjects on average spent 13.5 hours using the system. Clinical and kinematic data were collected pre and post study. The whole group improved on the Fugl-Meyer (FM) assessment and on six kinematic measurements. In addition, a combination of these kinematic measures was able to predict a substantial portion of subjects’ FM scores. Conclusion: The outcomes of this pilot study warrant further investigation of the system’s ability to promote recovery of hand function in subacute and chronic stroke.

Kinematic measures of brain drawings are associated with illness perceptions in people with stroke

2016 ◽  
Vol 28 (10) ◽  
pp. 1637-1642 ◽  
Author(s):  
Katharina Grünich ◽  
Vanessa Garcia-Hoyos ◽  
Cathy Stinear ◽  
Suzanne Ackerley ◽  
Jitske Tiemensma ◽  
...  
Keyword(s):  
Illness Perceptions ◽  
Emotional Health ◽  
Recurrent Stroke ◽  
Well Being ◽  
Stroke Severity ◽  
Kinematic Data ◽  
Patient Groups ◽  
Kinematic Measures ◽  
Larger Sample

ABSTRACTBackground:Previous research has shown that measuring the size and content of patients’ drawings of their illness can reveal their perceptions and predict recovery. This study aimed to assess the usefulness of analyzing kinematic features of drawings.Methods:A pilot observational study was conducted with 15 patients who had been hospitalized with a stroke 8 to 11 months previously. They were asked to draw a picture of what they thought had happened to their brain and describe the drawing using an electronic inking pen and digitizing tablet. Analysis of kinematic data (time to draw/write, drawing/writing speed, and pen pressure) was conducted using MovAlyzeR® software. Evaluations of physical functioning, quality of life, illness perceptions, and emotional well-being were administered, and correlations with kinematic measures assessed.Results:Stronger pen pressure was associated with perceptions of greater control over the stroke. Faster drawing was correlated with greater worry about a recurrent stroke and the perception that the effects of the stroke would last longer. Needing more time to write was associated with perceptions of fewer consequences of the stroke. No associations between kinematic measures and indicators of stroke severity, physical, or emotional well-being were shown.Conclusions:Kinematic measures of stroke patients’ drawings of their brain and comments were associated with illness perceptions and not measures of physical or emotional health status. The addition of kinematic analysis may add further utility to the assessment of patients’ drawings of their illness. More studies need to be performed with larger sample sizes and other patient groups.

Design and Development of H∞ and μ-Synthesis Controllers for Nanorobotic Manipulation and Grasping Applications

2007 ◽  
Author(s):  
Reza Saeidpourazar ◽  
Beshah Ayalew ◽  
Nader Jalili
Keyword(s):  
Degrees Of Freedom ◽  
Controller Design ◽  
Equations Of Motion ◽  
Dynamic Equations ◽  
Robust Controller ◽  
Accuracy And Precision ◽  
Highly Nonlinear ◽  
Linearized Model ◽  
High Level ◽  
Robust Controller Design

This paper presents the development of H∞ and μ-synthesis robust controllers for nanorobotic manipulation and grasping applications. Here a 3 DOF (Degrees Of Freedom) nanomanipulator with RRP (Revolute Revolute Prismatic) actuator arrangement is considered for nanomanipulation purposes. Due to the sophisticated complexity, and expected high level of accuracy and precision (of the order of 10−7 rad in revolute actuators and 0.25 nm in the prismatic actuator) of the nanomanipulator, there is a need to design a suitable controller to guarantee an accurate manipulation process. However, structure of the nanomanipulator employed here, namely MM3A, is such that the dynamic equations of motion of the nanomanipulator are highly nonlinear and complicated. Linearizing these dynamic equations of the nanomanipulator simplifies the controller design process significantly. However, linearization could suppress some critical information about the system dynamics. In order to achieve the precise motion of the nanomanipulator utilizing the simple linearized model, H∞ and μ-synthesis robust controller design approaches are proposed. Following the development of the controllers, numerical simulations of the proposed controllers on the nanomanipulator are used to verify the positioning performance.

scholarly journals Effects of vestibular neurectomy and neural compensation on head movements in patients undergoing vestibular schwannoma resection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Omid A. Zobeiri ◽  
Gavin M. Mischler ◽  
Susan A. King ◽  
Richard F. Lewis ◽  
Kathleen E. Cullen
Keyword(s):  
Vestibular Schwannoma ◽  
Normal Subjects ◽  
Head Movements ◽  
Head Motion ◽  
Vestibular Loss ◽  
Vestibular Neurectomy ◽  
Time Points ◽  
Head Kinematics ◽  
Kinematic Measures ◽  
Vestibular Damage

AbstractThe vestibular system is vital for maintaining balance and stabilizing gaze and vestibular damage causes impaired postural and gaze control. Here we examined the effects of vestibular loss and subsequent compensation on head motion kinematics during voluntary behavior. Head movements were measured in vestibular schwannoma patients before, and then 6 weeks and 6 months after surgical tumor removal, requiring sectioning of the involved vestibular nerve (vestibular neurectomy). Head movements were recorded in six dimensions using a small head-mounted sensor while patients performed the Functional Gait Assessment (FGA). Kinematic measures differed between patients (at all three time points) and normal subjects on several challenging FGA tasks, indicating that vestibular damage (caused by the tumor or neurectomy) alters head movements in a manner that is not normalized by central compensation. Kinematics measured at different time points relative to vestibular neurectomy differed substantially between pre-operative and 6-week post-operative states but changed little between 6-week and > 6-month post-operative states, demonstrating that compensation affecting head kinematics is relatively rapid. Our results indicate that quantifying head kinematics during self-generated gait tasks provides valuable information about vestibular damage and compensation, suggesting that early changes in patient head motion strategy may be maladaptive for long-term vestibular compensation.

scholarly journals Agreement between measurements of stance width using motion capture and center of pressure in individuals with and without Parkinson’s disease

2017 ◽  
Author(s):  
J. Lucas McKay
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Center Of Pressure ◽  
Study Groups ◽  
Quiet Standing ◽  
Strongly Correlated ◽  
Kinematic Data ◽  
Source Data ◽  
Two Measures ◽  
Kinematic Measures

AbstractBackgroundMany individuals with Parkinson’s disease exhibit narrow stance width during balance and gait. Because of this, stance width is an important biomechanical variable in many studies. Measuring stance width accurately using kinematic markers in parkinsonian patients can be problematic due to occlusions by research staff who must closely guard patients to prevent falls.MethodsWe investigated whether a measure of stance width based on the mediolateral distance between the center of pressure under each foot could approximate stance width measured with kinematic data. We assessed the agreement between estimates of stance width obtained from simultaneous kinematic and center of pressure measures during quiet standing in 15 individuals (n=9 parkinsonian, n=6 age-similar neurotypical). The source data (1363 unique trials) contained observations of stance width varying between 75–384 mm (≈25-150% of hip width).FindingsStance width estimates using the two measures were strongly correlated (r = 0.98). Center of pressure estimates of stance width were 48 mm wider on average than kinematic measures, and did not vary across study groups (F2,12=1.81, P<0.21). The expected range of differences between the center of pressure and kinematic methods was 14–83 mm. Agreement increased as stance width increased (P<0.02).InterpretationIt is appropriate to define stance width based on center of pressure when it is convenient to do so in studies of individuals with and without Parkinson’s disease. When comparing results across studies with the two methodologies, it is reasonable to assume a bias of 48 mm.

scholarly journals Development of the Home based Virtual Rehabilitation System (HoVRS) to remotely deliver an intense and customized upper extremity training

2020 ◽  
Author(s):  
Qinyin Qiu ◽  
Amanda Cronce ◽  
Jigna Patel ◽  
Gerard G Fluet ◽  
Ashley Mont ◽  
...  
Keyword(s):  
Upper Extremity ◽  
Chronic Stroke ◽  
Hand Rehabilitation ◽  
Kinematic Data ◽  
Virtual Rehabilitation ◽  
Home Based ◽  
Rehabilitation System ◽  
Kinematic Measures ◽  
And Training ◽  
Training Protocol

Abstract Background: After stroke, sustained hand rehabilitation training is required for continuous improvement and maintenance of distal function. Methods: In this paper, we present a system designed and implemented in our lab: the Home based Virtual Rehabilitation System (HoVRS). Fifteen subjects with chronic stroke were recruited to test the feasibility of the system as well as to refine the design and training protocol to prepare for a future efficacy study. HoVRS was placed in subjects’ homes, and subjects were asked to use the system at least 15 minutes every weekday for 3 months (12 weeks) with limited technical support and remote clinical monitoring. Results: All subjects completed the study without any adverse events. Subjects on average spent 13.5 hours using the system. Clinical and kinematic data were collected pre and post study in the subject’s home. Subjects demonstrated a mean increase of 5.2 (SEM=0.69) on the Upper Extremity Fugl-Meyer Assessment (UEFMA). They also demonstrated improvements in six measurements of hand kinematics. In addition, a combination of these kinematic measures was able to predict a substantial portion of the variability in the subjects’ UEFMA score. Conclusion: Persons with chronic stroke were able to use the system safely and productively with minimal supervision resulting in measurable improvements in upper extremity function.

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